SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9c9217bd28db250edd66b8a44ca7561664ff3c72c0d1d63a7a1cbc15f5380ce5' 
  AND token = 'dowt+Z7WL3xlHKuAzNht+bNcvl4B38HanhmFYps3OKw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}